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Prints are suddenly weak and brittle  

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espen fjellvaer.o
(@espen-fjellvaer-o)
Active Member
Prints are suddenly weak and brittle

Hi,

I have suddenly come to experience some weird printing issues. It seems most of my (PLA) prints suddenly are weak and brittle.
I tried printinting https://www.thingiverse.com/thing:1424970 but it comes out too weak, brittle and bendable to use. The outer layers/perimeters/walls are also struggling to adhere to the infill. I can easily crumble this whole print to pancake in my hands.

At first I thought it was something wrong with the model itself, so I tried good old Benchy instead.

She looks as stunning as ever, but she is kinda brittle. The first Benchy I printed is strong enough that I cannot break it by squeezing its hull or its railings (outer hull, but above the deck), but this new one I can break apart somewhat easily.

As far as I know I havent changed any print settings.

Posted : 11/02/2019 8:41 am
Sembazuru
(@sembazuru)
Prominent Member
Re: Prints are suddenly weak and brittle

Has it been humid where you are? One of the symptoms of filament that has absorbed too much moisture (from the air) is brittle prints.

Are you able to provide pictures of what your bad prints look like?

See my (limited) designs on:
Printables - https://www.printables.com/@Sembazuru
Thingiverse - https://www.thingiverse.com/Sembazuru/designs

Posted : 11/02/2019 9:04 am
espen fjellvaer.o
(@espen-fjellvaer-o)
Active Member
Topic starter answered:
Re: Prints are suddenly weak and brittle

It shouldn't have been too humid, but it is hard to say. It has been indoors, in a relatively small and warm room. The PLA roll i used now is about two weeks old, so it haven't had that much time to soak up humidity either.

I'll try and post some pictures later this evening.

Posted : 11/02/2019 11:10 am
jweaver
(@jweaver)
Honorable Member
Re: Prints are suddenly weak and brittle


It shouldn't have been too humid, but it is hard to say. It has been indoors, in a relatively small and warm room. The PLA roll i used now is about two weeks old, so it haven't had that much time to soak up humidity either.

I'll try and post some pictures later this evening.

I can't see how this is humidity. I am still using filament that I bought 4 years ago, and thave been left open and not seen anything like this (UK, warm house, relatively low humidity)

I have seen something like you describe wit a partially blocked nozzle.. Such that you are only laying down a fraction of the material.. it looks OK, but is very fragile.

Extrude some filament in thin air.. how does it look?

Posted : 11/02/2019 12:05 pm
Erik
 Erik
(@erik-3)
Estimable Member
Re: Prints are suddenly weak and brittle


I can't see how this is humidity. I am still using filament that I bought 4 years ago, and thave been left open and not seen anything like this (UK, warm house, relatively low humidity)

My roll of silver that came with my printer one year ago is now super brittle and gets almost no layer adhesion, even at 220º. I only use it for rapid prototyping, so I'm not worried about drying it out. PLA does absorb moisture, and it is completely dependent on how it is stored.

Posted : 11/02/2019 2:32 pm
espen fjellvaer.o
(@espen-fjellvaer-o)
Active Member
Topic starter answered:
Re: Prints are suddenly weak and brittle



It shouldn't have been too humid, but it is hard to say. It has been indoors, in a relatively small and warm room. The PLA roll i used now is about two weeks old, so it haven't had that much time to soak up humidity either.

I'll try and post some pictures later this evening.

I can't see how this is humidity. I am still using filament that I bought 4 years ago, and thave been left open and not seen anything like this (UK, warm house, relatively low humidity)

I have seen something like you describe wit a partially blocked nozzle.. Such that you are only laying down a fraction of the material.. it looks OK, but is very fragile.

Extrude some filament in thin air.. how does it look?

It looks well, but Im not sure if its wide enough. I have had some intermittent "extruder clicking", so it could indeed be that it is partially blocked(?). I will try and read up a bit on how best to clear the nozzle.

Posted : 11/02/2019 4:05 pm
espen fjellvaer.o
(@espen-fjellvaer-o)
Active Member
Topic starter answered:
Re: Prints are suddenly weak and brittle

I did a couple of cold pulls now, one of them sitting a while at 90 degrees before pulling it out. Really felt like it got a good "grip" before loosing.. Printed a new Benchy, but she still feels a bit weak. Underside is brittle, and Im pretty certain I still can crack the railings.

Could it be too low live Z?

Posted : 11/02/2019 6:22 pm
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